One man has been arrested and guns and ammunition have been seized in a garda raid.

The man, aged in his late 20s, was detained during searches at a halting site in the Northern Cross area of north Dublin early on Thursday morning.

He was taken in for questioning to Coolock garda station under section 30 of the Offences Against the State Act 1939.

At least four firearms and associated ammunition were seized.

Gardai said the search operation involved officers from the northern division, the special detective and emergency response units, the National Bureau of Criminal Investigations, the Garda helicopter, dog handlers and mounted police.

During the search of the halting site and surrounding land near the Darndale area, two pipe bombs were discovered.

The bomb squad was called in and made safe both devices, which they described as viable. The explosives were discovered in a disused outhouse on the site.

"The devices were made safe in situ without the need for a controlled explosion and then removed to a secure military location for further examination," said a spokesman for the Defence Forces.

Local residents were evacuated to a safe location when the devices were found and the bomb squad was on the scene for two hours.